The Catholic Church's system of canon law applies to its clergy in Australia and internationally.Because it lacks the binding force found in most countries' legal systems, it sits alongside the law of those countries, with which it occasionally conflicts.
Irrespective of the application of Australian criminal law, the Catholic church's negligent treatment of allegations of sexual abuse by members of its clergy represents a clear breach of its own legal code.
Early legal documents of the Catholic church started to be codified around 1200AD, through to significant revisions published by Pope Benedict XV in 1917, arising from the First Vatican Council of 1869-70. These were further overhauled following the 1962-65 Second Vatican Council called by Pope John XXIII.
Canon 915 reads: ''Those who have been excommunicated or interdicted after the imposition or declaration of the penalty and others obstinately persevering in manifest grave sin are not to be admitted to holy communion.''
Whether someone has been excommunicated, interdicted (censured) or penalised depends upon a decision of the church to exclude that person from the communion ritual, by which its adherents purport to consume the body or blood of Jesus Christ, in the form of a blessed wafer or wine.
In assessing whether someone persists in manifest grave sin, it is a similar process to proving the elements of a criminal offence.
In this case, a sin of some kind must be proven; second, it must be a ''grave'' sin; third, it must be ''manifest'' or widespread; last, it must be persevered in obstinately.
Based on the convictions to date of Catholic clergy in Australia, the US, Canada, Ireland and continental Europe, it is clear that not only sins, but criminal offences have occurred.
While canon law may comfortably conflict with domestic laws in some respects, we cannot just agree to disagree here. The sin and offence that we are examining is child sexual abuse.
Few crimes are worse.
One need only read Peter Fox's description of one harrowing encounter of a 12-year-old Maitland boy at the hands of convicted paedophile priest James Patrick Fletcher to be certain that this sin is exceedingly grave.
Fox describes the callousness with which Fletcher, who died in jail in 2006 after being convicted in 2004, coolly smoked a cigarette as the boy he had penetrated, to the point of drawing blood, sobbed.
While the level of physical abuse varies from case to case, the psychological damage done to the victims of paedophile priests is a common thread, often involving years of preparatory grooming.
Having established that grave sins are being perpetrated, it must be shown that the occurrences are manifest or widespread.
Some canon law scholars contend that for a sin to be manifest, it must be known by a large part of a community. This is where the Catholic church's notorious secrecy and interference kicks in to frustrate the sexual abuse of children being considered as a serious transgression of its own rules.
Almost all individual cases of child sexual abuse involve a victim who is too scared to make the abuse known to even one other person, let alone to a sufficient number to satisfy the ambiguous application of this rule.
But if we treat the instances of child sexual abuse at the hands of Catholic clergy collectively, the sheer volume of cases and their worldwide distribution renders this grave sin of the church as a whole as demonstrably ''manifest''.
So we have a collective manifestly grave sin on our hands. But it does not breach Canon 915 unless we can show that it is being persisted in obstinately.
Surely the church's continual stonewalling of investigators satisfies this final element. While there is some solace to be taken from Thomas Kenneth Brennan being charged with concealing the crimes of other priests, despite his pre-trial death, this lone case to date demonstrates the unwillingness of church officials to co-operate with investigators.
NSW Premier Barry O'Farrell's recent announcement of a commission of inquiry into police investigations of alleged paedophile priests in the Hunter region should be welcomed.
As well as being an avenue for discovering truth and approaching reconciliation within Australian domestic law, it would provide the Catholic Church with an opportunity to revise the application of its own revered canons, particularly to those who suppose to promote them.